It could also be the Java Plug-in. I'd just disable Java, if you don't really need it, most people don't. Here is how: How to turn off Java applets

Hope that helps.

Hi pclind, this is probably related to extensions. You can try it out easily by starting Firefox in Safe Mode. Here is how: [[Troubleshoot Firefox issues using Safe Mode]]
It could also be the Java Plug-in. I'd just disable Java, if you don't really need it, most people don't. Here is how: [[How to turn off Java applets]]
Hope that helps.

I tried the two suggestions. Turning of java didn't make any difference. But running in safe mode with no plug-ins did work. These messages popping 4-6 times every time a page is loaded, started when I upgraded to beta 17.0 from the previous beta release.

I tried the two suggestions. Turning of java didn't make any difference. But running in safe mode with no plug-ins did work. These messages popping 4-6 times every time a page is loaded, started when I upgraded to beta 17.0 from the previous beta release.

If it does work in Firefox Safe-mode then disable all extensions (Tools > Add-ons > Extensions) and then try to find which is causing it by enabling one extension at a time until the problem reappears.

If it does work in Firefox Safe-mode then disable all extensions (Tools > Add-ons > Extensions) and then try to find which is causing it by enabling one extension at a time until the problem reappears.
Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")
See also:
*https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

I found the problem to be in the extension SocialFIxer 7.201. I have notified the author on his Facebook page https://www.facebook.com/Socialfixer
Matt also has info on his website at http://socialfixer.com/
Thanks for the info on how to track it down!

Helpful Reply

I was having the error
Java Error message: evalInSandbox:SyntaxError: syntax error.
Social Fixer has it corrected in version 7.301, and I am using Firefox 17.0 beta with Social Fixer 7.301 and not having any more of the errors.

I was having the error
Java Error message: evalInSandbox:SyntaxError: syntax error.
Social Fixer has it corrected in version 7.301, and I am using Firefox 17.0 beta with Social Fixer 7.301 and not having any more of the errors.

I get the huge wave of Java messages since I upgraded to 17. Tried to revert to 16. That didn't work. I don't have SocialFixer Installed, or at least it's not in my add-ons list. And now I can't run except with all add-ons disabled.

Looks like it might be time to switch browsers again.

I get the huge wave of Java messages since I upgraded to 17. Tried to revert to 16. That didn't work. I don't have SocialFixer Installed, or at least it's not in my add-ons list. And now I can't run except with all add-ons disabled.
Looks like it might be time to switch browsers again.